|
|
|
|
|
Capacities
of Various DVD
DVD Format Books
|
| |
|
There
are a number of variations of DVD technology to meet the needs
of both the home entertainment and computer environments. It is
also important to understand the difference between the physical
formats (such as DVD-ROM or DVD-R) and the application formats
(such as DVD-Video or DVD-Audio). A superb FAQ on DVD is available
from dvddemystified.com
and should answer most questions.
DVD-Video (application
format)
Read-only storage intended for the playback of
video content, such as movies, in consumer DVD players or DVD
drives in a PC.
DVD-Video
features
DVD-ROM (physical format)
Read-only storage intended for PCs. Essentially
a much higher capacity CD-ROM, that can also store MPEG2 video,
AC3 audio, and traditional PC content. This format is ideal for
PC content such as games, reference materials and other data intensive
applications.
DVD-R (physical format)
DVD Recordable. A DVD format which supports write-once,
read-many. The target usage model includes archiving, software
development and low-volume data distribution.
DVD-RAM (physical
format)
A DVD format which supports write-many, read-many
storage. Example applications include short-term archiving, software
development, and media recording. DVD-RAM is a rewritable format
supported by the DVD-Forum.
DVD+RW
(physical format)
DVD+RW doesn't have the same problem as DVD-RAM
as discs can be played in existing DVD players. DVD+RW disks hold
4.7 gigabytes of data. DVD+RW is a rewritable disc format that
is designed to be highly compatible with DVD-ROM drives and players.
It has the same sector and Error Correction Code (ECC) block layout,
the same modulation code, and a very similar logical layout as
DVD-ROM.
- Supported
by: Hewlett-Packard, Mitsubishi Electric, Philips, Ricoh,
Sony, and Yamaha
DVD-RW
(physical format)
DVD-RW is the other rewriteable format alongside
DVD-RAM officially supported by the DVD Forum. DVD-RW discs are
playable in Pioneer DVD players and some players from other manufacturers.
Capacity is 4.7GB
DVD-Audio
This format focuses on music and other forms of
audio-only content. This is the only DVD format which has not
been finalised and as yet remains to be seen whether it ever really
will.
|
| |
An
Overview of Read/Write Compatibility
|
Drive
type
|
DVD-RAM
|
DVD+RW
|
DVD-R/W
|
MMVF
|
|
Main
supporters of format & manufacturers:
|
Toshiba,
Matsushita (Panasonic), Hitachi, Mitsubishi, JVC
|
Sony,
Philips, Hewlett-Packard, Ricoh, Yamaha
|
Pioneer
|
NEC
|
|
Capacity
per side
|
2.6GB/4.7GB
|
3GB
|
3.95GB
|
5.2GB
|
|
CD-ROM/
Audio CDs
|
Read
media
|
Read
media,
write format *
|
Media
not compatible
|
Not
yet determined
|
|
CD-R/
CD-RW disks
|
Read
media
|
Read
media,
write format *
|
Media
not compatible
|
Not
yet determined
|
|
DVD-Video/
DVD-ROM disks
|
Read
media,
write format **
|
Read
media,
write format
|
Read
media,
write format
|
Read
media,
write format
|
|
Panasonic
PD disks
|
Read
media
|
Media
not compatible
|
Media
not compatible
|
Media
not compatible
|
|
DVD-RAM
disks
|
Read
and write media
|
Media
not compatible
|
Media
not compatible
|
Not
yet determined
|
|
DVD+RW
disks
|
Media
not compatible
|
Read
and write media
|
Media not compatible
|
Not
yet determined
|
|
*
Write compatability is planned (as usual) for the second generation.
** By late 1998 some manufacturers plan to produce DVD-ROM drives
that will be able to read DVD-RAM disks, though whether this will
actually become reality is another matter. |
|
|
|
|
|
Read/Write
|
Read
|
|
|
|
|
DVD-RAM
|
DVD-ROM
CD-ROM/XA
DVD-R
CD-Audio
DVD-Video
CD-R
Video CD
CD-RW
|
|
|
DVD
Format Books
The DVD specifications are documented in a group of five books:
Book
A: DVD-ROM Specification
Book B: DVD-Video Specification
Book C: DVD-Audio Specification
Book D: DVD-R Specification
Book E: DVD-RAM Specification
Capacities
of DVD
For
reference, a CD-ROM holds about 650 MB (megabytes), which is 0.64
GB (gigabytes) or 0.68G bytes (billion bytes). In the list below,
SS/DS means single-/double-sided, SL/DL means single-/dual-layer,
GB means gigabytes (2^30), G means billions of bytes (10^9).
DVD-5
(12cm, SS/SL): 4.38 GB (4.7 G) of data, over 2 hours of video
DVD-9 (12cm, SS/DL): 7.95 GB (8.5 G), about 4 hours
DVD-10 (12cm, DS/SL): 8.75 GB (9.4 G), about 4.5 hours
DVD-18 (12cm, DS/DL): 15.90 GB (17 G), over 8 hours
DVD-1 (8cm, SS/SL): 1.36 (1.4 G), about half an hour
DVD-2 (8cm, SS/DL): 2.48 GB (2.7 G), about 1.3 hours
DVD-3 (8cm, DS/SL): 2.72 GB (2.9 G), about 1.4 hours
DVD-4 (8cm, DS/DL): 4.95 GB (5.3 G), about 2.5 hours
DVD-R (12cm, SS/SL): 3.68 GB (3.95 G)
DVD-R (12cm, DS/SL): 7.38 GB (7.9 G)
DVD-R (8cm, SS/SL): 1.15 GB (1.23 G)
DVD-R (8cm, DS/SL): 2.29 GB (2.46 G)
DVD-RAM (12cm, SS/SL): 2.40 GB (2.58 G)
DVD-RAM (12cm, DS/SL): 4.80 GB (5.16 G)
DVD-RAM (12cm) Double Sided - 9.4GB
Tip:
It takes about two gigabytes to store one hour of average video.
Capacity
Measurements
There's an unfortunate confusion of units of measurement in the
DVD world. For example, a single-layer DVD holds 4.7 billion bytes
(G bytes), not 4.7 gigabytes (GB). It only holds 4.38 gigabytes.
Likewise, a double-sided, dual-layer DVD holds only 15.90 gigabytes,
which is 17 billion bytes.
The problem is that "Kilo-," "Mega-," and
"Giga-" generally represent multiples of 1000 (10^3,
10^6, and 10^9), but when used in the computer world to measure
bytes they generally represent multiples of 1024 (2^10, 2^20,
and 2^30). Both Windows and Mac OS list volume capacities in "true"
megabytes and gigabytes, not millions and billions of bytes
Most DVD figures are based on multiples of 1000, in spite of using
notation such as GB and KB/s that traditionally have been based
on 1024. The "G bytes" notation does seem to consistently
refer to 10^9. The closest there is to an unambiguous notation
is to use "kbps" for thousands of bits/sec, "Mbps"
for millions of bits/sec, "kilobytes" for 1024 bytes,
"megabytes" for 1,048,576 bytes, and "gigabytes"
for 1,073,741,824 bytes.
RV
- 230998 / RV-150900 / LRV-310501
|
|
|
|
